Integrating Livestock Grazing and Sympatric Takin to Evaluate the Habitat Suitability of Giant Panda in the Wanglang Nature Reserve

Habitat suitability provides essential information for the management of protected species. However, studies that jointly consider the impacts of human disturbance and sympatric animals in habitat suitability assessments of giant panda are limited, which may overestimate the habitat status. To address this issue, we evaluated the habitat suitability of giant panda in Wanglang Nature Reserve by simultaneously investigating livestock grazing and sympatric takin via MAXENT, a new attempt at the assessment of the habitat suitability of giant panda. We focused on describing the habitat suitability of giant panda and determining the habitat overlap between livestock, takin, and panda to evaluate the impacts of livestock grazing and sympatric takin on the suitable giant panda habitat. Results revealed that only 16.33% of the area in Wanglang was suitable giant panda habitat, of which 67.66% was shared by livestock, and 97.99% of the remaining suitable panda habitat not shared by livestock was revealed to be shared by takin. The results indicate an unfavorable habitat status of giant panda in Wanglang, with the potential extensive habitat overlap between livestock, takin and panda exerting further pressure. Thus, to effectively protect giant pandas and their habitats, grazing activity should be controlled. Furthermore, to accurately protect sympatric animals, the monitoring of panda and takin activities in the overlapping areas must be maintained.

Habitat overlap and body condition in aquatic turtles: are there additive effects between invasive and native species?

Trachemys scripta (Reptilia, Emydidae) is among the most widespread invasive reptiles in the world. In general, it is assumed that this species has negative effects on native aquatic turtles based on experiments conducted under controlled conditions. Here, we analysed a 7‒year time series (2013‒2019) of data from captures of three species of turtles (two natives and one alien) from natural populations in the northeastern Iberian Peninsula. We evaluated (i) the interspecific spatial overlap and (ii) the correlation between the scaled mass index (SMI) of the native turtles and the abundance of T. scripta, including an interaction effect between the species. The analyses revealed that T. scripta has relatively low spatial overlap with Emys orbicularis but high overlap with Mauremys leprosa. Overall, the abundance of T. scripta was not associated with significant variations in the SMI of the native species, although for the female E. orbicularis, we detected a negative trend. The analyses also indicated that the abundance of T. scripta does not have an additive effect on the SMI of other turtles, even if there is a negative effect between native species. These findings suggested that the impact of T. scripta on other turtles could be density-dependent.

Factors Associated with Habitat Segregation Among the Four Species of Cervids in the Chitwan National Park, Nepal

Study of habitat segregation among the four species of cervids was conducted in the Chitwan National park of lowland Nepal. This study aimed to investigate the possible mechanisms of habitat partitioning among the four cervids - chital, sambar deer, hog deer and northern red muntjac using discriminant analysis and canonical correlation analysis. Present study considered four major niche dimensions - habitat, human disturbance, presence of predators and seasons. The data were collected by walking along the line transects that encompasses the different habitats, varying degree of human disturbances and frequency of predator’s presence. Results showed the significant effect of season on the habitat segregation among these cervids. There was higher niche overlap during summer season as compared to winter season. Habitat overlap between chital and muntjac was higher and unstable than others, which showed that they were the competitors of the same resources as enlightened by their generalist nature. Therefore, maintaining habitat heterogeneity and minimizing human disturbances will be better solutions for the coexistence of herbivores in the Chitwan National Park and can be an example for similar areas of lowland Nepal.

Rainbow trout (Oncorhynchus mykiss) habitat overlap with wild Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in natural streams: do habitat and landscape factors override competitive interactions?

The purpose of this study was to update rainbow trout (Oncorhynchus mykiss) invasion status, delineate factors that increase the invasion probability, and quantify habitat overlap between invasive rainbow trout and native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) on Prince Edward Island, Canada. Analysis of landscape-level variables in 26 watersheds (14 with and 12 without rainbow trout) demonstrated that watershed slope, percent agricultural land use, and distance to the nearest rainbow trout population significantly increased the probability of rainbow trout establishment. Two independent reach-level fish community surveys were conducted by electrofishing in combination with habitat surveys. Reaches with rainbow trout had higher stream slope, Atlantic salmon were found in wider reaches with larger substrate, and brook trout were typically dominant in headwater reaches with finer substrate. Findings at multiple ecological scales illustrated that rainbow trout invasion success is positively influenced by the presence of high-slope habitat. Habitat separation of the three salmonid species indicates that competition with introduced rainbow trout may not be the most significant threat to native salmonid populations.